((a)) ** General rule** Except as provided in subsection (b), for each fiscal year for which an eligible agency receives assistance under this chapter, the eligible agency shall provide, from non-Federal sources for the costs the eligible agency incurs for the administration of programs under this chapter, an amount that is not less than the amount provided by the eligible agency from non-Federal sources for such costs for the preceding fiscal year.

((b)) ** Exception** If the amount made available from Federal sources for the administration of programs under this chapter for a fiscal year (referred to in this section as the “determination year”) is less than the amount made available from Federal sources for the administration of programs under this chapter for the preceding fiscal year, then the amount the eligible agency is required to provide from non-Federal sources for costs the eligible agency incurs for the administration of programs under this chapter for the determination year under subsection (a) shall bear the same ratio to the amount the eligible agency provided from non-Federal sources for such costs for the preceding fiscal year, as the amount made available from Federal sources for the administration of programs under this chapter for the determination year bears to the amount made available from Federal sources for the administration of programs under this chapter for the preceding fiscal year.